The National Eye Institute, as part of its mission, is committed to helping the world's developing countries combat blinding eye diseases. This requires information about the prevalence, incidence, and causes of blindness and visual disability and impediments to the reduction of these conditions on an international level. This information is necessary to identify research opportunities that may provide basic knowledge about etiologies and opportunities for the transfer of new knowledge developed by NEI-supported scientists to locations where this new knowledge may contribute to the alleviation of blindness and visual disability. A contractual arrangement between NEI and the World Health Organization has been in effect since 1979 with the goal of strengthening the Program for the Prevention of Blindness world-wide. In this contract period, work will include: evaluation of selected national blindness prevention programs with regard to disease prevalence, impact on service delivery, patient outcomes, and assessment of global economic burden including direct monetary costs and personal costs related to a range of quality of life issues;assessment of the magnitude and type of refractory anomalies in school-age children and in adults from different ethnic/cultural settings;and provision of technical assistance and guidelines for providing appropriate eye care and monitoring of eye-care delivery outcomes.